Automatic keyhole cover for cylinder locks



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Feb. 12, 1963 E. N. JACOB] 3,077,101 AUTOMATIC KEYHOLE COVER FOR"CYLINDER LOCKS Original Filed Oct. 19, 1959 3 Sheets-Sheet 1 Feb. 12,1963 E. N. JACOB! 3,077,101

AUTOMATIC KEYHOLE COVER FOR CYLINDER LOCKS Original Filed Oct. 19, 1959AUTOMATIC KEYHOLE COVER FOR CYLINDER LOCKS Original Filed 001:. 19. 1959Feb. 12, 1963 N, A Bl 3,077,1 0;

"um H.

llnite States Patent Ofilice 3,?7,ll Patented Feb. 12, 1963 Edward N.Jacobi, Wis, assignor to Briggs dz Etratton (Corporation, Milwaukee,Wis, a corporation of elaware Qontinuation of application Ser. No.tldLZflZ, Get. 1%,

195?. This application Aug. '7, 1951, Ser. No. 130,236 lll Claims. (Ci.7tl-45'5) This application is a continuation of my copendingapplication, Serial No. 347,292, filed October 19, 1959, now abandoned.

This invention relates to key controlled locks and refers moreparticularly to dust covers for the open end of the keyhole in suchlocks. The conventional tumbler lock which is widely used in automobilescomprises a cylinder rotatably mounted in a bore in a housing and havinga key receiving slot opening to its front end. When such locks areinstalled in the doors and rear deck lids of automobiles, they arenaturally exposed to precipitation, such as rain and snow, as well as todust and dirt, all of which can injure the lock mechanism, or at leastinterfere with its operation; and it is therefore desirable to provide aclosure or dust cover for the front of the key receiving slot in thecylinder whereby the entry of such foreign matter into the lockmechanism is prevented.

One type of dust cover heretofore used had a cover member hingedlyconnected to the lock mechanism to swing down over the front of thecylinder. It was necessary to lift the cover member before the key couldbe inserted into the lock, and this was frequently inconvenient,especially where the person wishing to open the lock was carryingpackages and did not have both hands free.

Another type of prior dust cover, illustrated in Patent No. 2,213,814 toE. N. Jacobi, had a closure member that was pivotally connected to thehousing for edgewise swinging motion to and from a the front of thecylinder. This dust cover could be swung aside by means of the key, butit was inconvenient because it required the key to be moved laterallybefore it could be inserted into the lock.

Patent No. 1,965,942 to E. N. Jacobi illustrates a dust cover that couldbe opened by axial inserting motion of the key. It comprised a capsecured over the front of the cylinder and having an aperture in linewith the mouth of the key slot, while a gate-like cover member wasmounted directly behind the cap for edgewise sliding motion transverselyto the cylinder axis, to and from a position closing the aperture in thecap. The cover memher was spring biased to its closed position, and oneside edge of it was beveled to provide a cam surface by which it couldbe forced sideward, against its bias, by the nose of a key beinginserted into the lock.

The angle of inclination of the cam surface on the cover member in thedust cover just described was necessarily a rather shallow one, andtherefore a substantial force had to be exerted upon the key to move thecover member sideward to its open position. Since the cam surfacetranslated rearward key inserting force into sideward opening force uponthe cover member, friction between the key and the cam surface was veryhigh, and in some cases was almost as great as the sideward cammingcomponent, so that the cover member offered very substantial resistanceto key insertion. A lock having such a dust cover also tended to betroublesome when the closure was coated with ice since the ice had to besubstantially entirely removed in order to permit the cover member to beengaged by the key and forced sideward thereby to its open position.

closed position overlying By contrast, it is an object of the presentinvention to provide a dust cover for the key receiving slot in a lockof the character described which opens readily in response to axialinserting force upon the key, and which thus requires no preliminarymotion to open the dust cover before the key can be inserted into thelock.

Another object of this invention is to provide a keyhole closure or dustcover for automotive door and rear eck locks which can be easily openedwhen coated with ice, and from which a coating of ice can be readilybroken away by means of the key, the shutter portions of the closurebeing yieldable inwardly to facilitate breaking of the ice by a keyjabbed into the key openin A further object of this invention resides inthe provision of a dust cover of the character described comprising anapertured cap mounted over the front of the cylinder and a cover memberwhich lies behind said cap and is movable to and from a positionblocking the aper ture in the cap, wherein the cover member is normallyheld in its closed position and is also urged into sealing engagementwith the cap by spring means which exerts a forward bias upon the covermember so that the cover iember can be readily displaced to its openposition by the nose of a key being inserted into the aperture in thecap.

The invention has for another of its objects the pro vision of a keyholedust cover of the character described wherein the shutter or covermember may have both sliding and rocking motion to and from its closedposition so that no delicate and expensive hinge or pivot is mbodied inthe dust cover of this invention, but the movements of the cover memberare nevertheless attended by very little friction, thus assuring botheasy displacement of the cover member by a key being inserted into thelock and prompt automatic return of the cover member to its closedposition when the key is withdrawn. it is also an object of thisinvention to provide a key slot closure or dust cover of the characterdescribed which occupies relatively little space on the front of thelock despite the fact that its cover member is biased forwardly and isadapted to be displaced to its open position by means of a key beinginserted straight rearwardly into the key slot.

Still another object of this invention resides in the provision of a keyslot closure of the character described, comprising an apertured capmounted over the front of the lock cylinder and a cover member whichlies behind the cap and is movable to and from a position closing theaperture in the cap, wherein spring means reacting between the covermember and the front of the cylinder biases the cover member intosealing engagement with the cap as well as urging it to its closedposition, and also biases the cap forwardly into sealing engagement withan annular retaining member by which the cap is rotatably held in placeover the front of the cylinder.

With the above and other objects in view which will appear as thedescription proceeds, this invention resides in the novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims, it beingunderstood that such changes in the precise embodiment of thehereindisclosed invention may be made as come within the scope of theclaims.

The accompanying drawings illustrate several comlete examples of thephysical embodiments of the invention constructed according to the bestmode so far devised for the practical application of the principlesthere of, and in which:

FIGURE 1 is a perspective view of a lock embodying the key slot closureor dust cover of this invention, installed on the rear deck of anautomobile, parts of the deck lid being broken away to show the lock;

FIGURE 2 is a fragmentary sectional view taken on the plane of the line22 in FIGURE 1, but with the rear portion of the lock itself shown inelevation;

FIGURE 3 is a viewsimilar to FIGURE 2 but showing the dust cover beingheld in its open position by means of a key inserted partway into thelock cylinder;

FIGURE 4 is a fragmentary side view of the lock mechanism shown inFIGURE 1 with portions of the lock housing and lock mounting meansbroken away and shown in section;

FIGURE 5 is a disassembled perspective view of the dust cover shown inFIGURES 1-4, together with the front portion of a lock on which the dustcover is installed;

FIGURE 6 is a fragmentary sectional view taken substantially on theplane of the line 6--6 in FIGURE 2;

FIGURE 7 is a fragmentary side view of a lock having the dust cover ofthis invention, with a modified form of rear deck lid mounting for thelock and with portions of the lock housing and its mounting means brokenaway and shown in section;

FIGURE 8 is a view similar to FIGURE 2 but showing a modified embodimentof the dust cover of this invention on a lock mounted with the lockmounting means shown in FIGURE 7; and

FIGURE 9 is a view similar to FIGURE 8 but showing the dust cover heldin its open position by means of a key inserted partway into the lockcylinder.

Referring now more particulmly to the accompanying drawings, in whichlike numerals designate like parts throughout the several views, thenumeral 4 designates generally a cylinder lock mechanism of the typecommonly used on automobiles, incorporating a dust cover 5 of thisinvention, shown installed, by way of example, on an automobile reardeck lid 6. It will be recognized that the dust cover of this inventionis also advantageously applicable to locks installed in automobiledoors, as well as touc -automotive locks installed in various exposedlocations.

As is conventional, the deck lid 6 may comprise spaced apartsubstantially parallel inner and outer panels 7 and 8, and the lockmechanism may extend through one or both panels. The lock mechanism isof the well known type comprising a housing 9 having a bore 1% openingto its front, and having a cylinder 11 rotatably mounted in the bore. Anaxially extending slot 12 in the cylinder, opening to the front thereof,is adapted to receive a key 13 by means of which the cylinder may berotated in opposite directions to defined locked and unlocked positions.

The lock mechanism may be mounted in a variety of ways. As shown inFIGURES 1-4, it is provided at its rear with means defining a forwardlyfacing shoulder 14 engaged with the inner face of the inner deck lidpanel '7, which means may comprise a nut 15 threaded onto the inwardlyprojecting rear portion 16 of the lock housing. At its front the lockhousing has integral radially projecting flange portions 17 at its sidesand lugs 18 projecting upwardly and downwardly at its top and bottom.Over the front of the housing is secured a bezel 19 which may comprisean ornamental trim member and which has an opening 19 coaxial with thecylinder and at least as large in diameter. Rearwardly projecting studs20 on the bezel 19 extend through closely fitting holes in the lugs 18on the front of the lock housing and have their rear end portions peenedover to fasten the bezel to the housing. The bezel overlies the outerface of the outer panel 8 of the rear deck lid and thus cooperate withthe nut 15 to prevent axial displacement of the lock housing.

In addition to its function as a lock mounting member, the bezel alsocooperates to hold in place on the front of the lock mechanism the dustcover of this invention, which comprises, in general, a dome-shaped cap21 having a key receiving aperture 22. in line with the key slot 12 inthe cylinder, an annular retainer 23 by which the cap is heldcoaxialwith the cylinder and which provides a if. sealing connectionbetween the cap, the lock housing 9 and the bezel l9, and a pair ofcover members 24 which are movable to and from positions in which theyclose the aperture 22in the cap.

The cap 21, which overlies and is spaced forwardly from the front of thecylinder with its convex surface outward, has a radially projectingsubstantially planar rim portion 26 around the periphery of itsdome-like, substantially hemispherical medial portion 27, and has arearwardly projecting annular flange 28 around the outer edge of its rimportion. Projecting rearwardly from the flange 23 on the cap are aplurality of narrow fingers 29 which are received in lengthwiseextending grooves 39 in the side of the cylinder that open to its frontend, thus providing a splined connection between the cap and thecylinder whereby the cap is permitted to have axial translatory motionrelative to the cylinder but is constrained to rotate therewith so thatthe aperture 22 in the cap is always in register with the key slot 12 inthe cylinder. To facilitate proper alignment of the aperture 22 in thecap withthe key slot 12 in the cylinder, one of the fingers 29 may besomewhat longer than the others, to be received in a groove in thecylinder that has a correspondingly greater axial length. It will beobserved that the cap, including the rim portion 26, the rearwardlyprojecting flange 28, and the fingers 2%, may be readily formed as aunitary stamping. Because the cap has a substantially larger diameterthan the cylinder, the front end portions 25 of the fingers are disposedobliquely to the cylinder axis, converging rearwardly toward oneanother, and to provide clearance for these portions of the fingers thefront of the bore in in the lock housing is divergingly enlarged, as at50.

The annular retainer 23, which may be formed as a unitary stamping, hasa substantially planar flange 32 at itsfront against the rear face ofwhich the rim portion 26 of the cap is engaged, and a larger diameterrearwardly offset rear flange 33, the front face of which flatwise bearsagainst the bezel 1.9, around the aperture 19' therein. A short axiallyextending portion 34 of the retainer, connecting the front flange 32 andthe rear flange '33, embraces the rearwardly projecting flange 28 on thecap to constrain the cap to rotation coaxially with the retainer. Areai-wardly projecting skirt 35 on the retainer embraces the front ofthe lock housing. Lugs or tangs 36, projecting rearwardly from the skirt35 of the retainer, at opposite sides thereof, have their rear endportions bent around the flanges 17 of the lock housing,as at 37, tohold the retainer on the lock housing before the latter is secured tothe bezel. At its top and bottom the lock housing has forwardly openingarcuate slots 38 in its front face, where the lugs 18 project therefrom,in which portions of the skirt 35 are received.

The cover members 24 overlie the rear concave surface of. the cap andnormally cooperate with one another to close the key receiving aperture22 in the cap. However, they are readily displaceable by means of a keyinserted into the aperture, to admit the key to the key slot 12 in thecylinder. Each cover member has a bearing portion 39 with a sphericallyconvex front surface, the radius of which is substantially identicalwith that of the concave inner or rear surface of the cap. The portions46 of the rear face of the cap at each side of the aperture 22; thereinconstitute thrust receiving surfaces which are inclined forwardly andtoward the aperture, and the bearing portion 39 of each cover memberslidably and rockably rides on one of thesethrust receiving surfaces.

Each. cover member has a shutter portion 41 extending from one side ofits bearing portion and disposed at a rearwardly inclined angle thereto,adapted to project radially inwardly beyond the edge of the aperture 22.in the cap. Preferably the shutter portion of each cover memher isrearwardly and radially inwardly inclined when the shutter is'in itsclosed position, but it could obviously be at such an angle to thecylinder axis as to lie normal thereto when the shutter member is in itsnormal closed position, the main consideration being that the shutterportion be disposed rearwardly of the edges or" the aperture 2.2 in thecap. The shutter portion terminates in a straight, fiat marginal edgeportion that provides a lip 42 which is adapted to fiat-wise abut thelip on the other cover member and cooperate therewith to seal theaperture 22 in the cap.

Each of the cover members is yieldingly biased toward the other, toeffect such engagement of their lips, by means of a coiled compressionspring 453*, all but the front few coils of which are received in aforwardly opening well in the front portion of the cylinder and thefront coil of which engages a rearwardly facing abutment d5 on the covermember. A straight strip integral with the bearing portion of the covermember and extending laterally therefrom at the side thereof remote fromits shuttor portion is bent laterally inwardly over the rear of thebearing portion to provide the abutment 45 against which the springreacts, and a rcarwardly bent end portion of the strip provides a tangor pilot which extends into the coils of the spring to hold it engagedwith said abutment. The tongs as are long enough to extend back into themouths of the wells i t when the cover members are in their openpositions to constrain the cover members to rotate with the cylinder,and the tangs also cooperate with the wells in rcsistiru displacement ofthe coils of the springs out of substantial coaxiality with one another.

The cover members are urged substantially strai -ht forwardly by thesprings 43, but because of the forward and radially inward inclinationof the thrust receiving surfaces on the cap, the bearing portions of thecover members tend to slide laterally toward one another over saidsurfaces in response to the biasing force of the springs, and thesprings thus serve to hold the lips of the two cover members firmlyengaged. Moreover, since the spherical radius of the front surface ofthe bearing portions of the covers matches the concavity of the thrustreceiving surfaces of the cap, the forward bias which the springs exertupon the cover members holds the latter in good surface-to-surface sea gengagement with the when the cover members are in their closedpositions. The forward thrust exerted upon the can by the springs,through the cover members, also biases the rim portion 26 of the capinto good sealing engagement with rear face of the front flange 32 onthe retainer; and the retainer, in turn, is urged forwardly to firmlythe front face of its rear flange 33 against the rear face of the bezel19, around the marginal edge of the opening 19" therein. The retainerthus provides a seal between the cap, the lock housing and the bezel.

In the lock mounting depicted in FEGURES 7-9, the lock housing has lugs118 at its top and bottom, the front faces of which are flush with thefront of the lock housing and which underlie a panel 168 or the like onwhich the lock is mounted. Studs 12%, projecting rearwardly from thepanel, extend through aligned holes in the lugs lib, and clips M1 on therear end portions of the studs hold the lock housing against the rear ofthe panel, with the lock cylinder coaxial with an aperture M9 in thepanel. The annular retainer 23 is confined between the panel and thecap, with the front face of the rear flange 33 of the retainer engagingthe marginal edge of the panel around said aperture and with the axiallyextending portion 34 of the retainer piloted in the anerture to hold theretainer coaxial with the aperture and thus with the cylinder. The rimportion 26 on the cap bears against the front flange 32 of the retainerunder forward bias exerted by the springs 43 acting through the c vermembers, and the retainer thus affords a seal between the cap, the lockhousing and the panel whereby the cap is permitted to rotate with thecylinder.

When the cover members are in their closed positions, their shutterportions ll are inclined rearwardly from the edges of the aperture 22 inthe cap at a substantially steep angle, as best seen in FIGURE 2, andtherefore they may be readily wedged apart by means of a key insertedbetween them, through said aperture 22. The rearward key inserting forceupon the cover members, exerted substantially laterally outwardly uponthem because of the inclination of their shutter portions, cooperateswith the forward biasing force of the springs to move the cover membersslidingly and rockingly on the thrust receiving surfaces 4t) of the cap.Forwardly projecting fingers 52 on the front of the lock cylinder,disposed in pairs at each side of the key slot and extending to within ashort distance of the thrust receiving surfaces ill, engage the rearfaces of the cover members as the latter are displaced by a key insertedbetween them and tend to confine the cover members to sliding motion onthe thrust receiving surfaces. As the cover members are moved to theiropen positions, the tangs 45 extend into slot-like spaces 53 be tweenthe pair of fingers 52 at each side of the key slot. To facilitate suchrocking motion of the cover members as is permitted by the fingers 52,the bearing portion of each cover is curved or rounded, as at 47, alongits marginal edge portion remote from the shutter. It will beappreciated that the rearward yieldabillty of the shutter portionsmakesit easy to dislodge a coating of ice from the closure, a straight inwardjab with the key frequently being all that is necessary to punch the keythrough the ice and past the shutters into the key slot 12.

When the key is withdrawn, the cover members automatically resume theirclosed positions under the influence of the springs 43. To insure thatthe cover members will not be displaced lengthwise of their lips, thebearing portion of each cover member has arcuate flanges 43 along itsopposite edges which fiatwise overlie the rear face of the rim portion26 on the cap when the cover members are in their closed positions andwhich thus cooperate with the spherical surfaces of the bearing portionsand cap to erve as locating means.

Some space is needed between the cap and the front of the lock cylinderto accommodate the rearward component of motion of the cover members,and most of this is provided by the concavity of the cap itself. Theretainer 23 also serves to provide such space because its axially offetfront flange 32 holds the cap with its rear edge spaced lightlyforwardly of the front of the cylinder. The wells i lin the cylinder inwhich the rear portions of the springs 4-3 are received can havesubstantial depth, since they are spaced from the sides of the keyreceiving slot 12 where they do not interfere with the tumblermechanism, and consequently the springs can be relatively long toprovide good biasing action. It will be noted that the springs aresubstantially steadied by the confinement of their rear end portions inthe wells so that they cannot be displaced by any lateral motion of thecover member prior to entry of the rear portions of the tangs 45 intothe mouths of the wells.

In the embodiment of the invention shown in FIGURES 8 and 9 there isonly one cover member 124, which has a shutter portion 141 wide enoughto extend entirely across the aperture 122 in the cap. The lip 142 onthe cover member cooperates with a fixed lip 24?; on the cap, defined byan inturned wall portion extending straight back from the aperture 122along one edge thereof. The fixed lip 242 may, of course, be formedintegrally with the cap by bending back the metal struck out of the keyreceiving aperture 122.

As in the previously described embodiment of the invention, the spring43 reacts between the bottom of a forwardly opening well 44 in thecylinder and a rearwardly facing abutment 45 on the cover member to biasthe cover member forwardly, and the inclination of the thrust receivingsurface All on the cap at the side of the aperture 122 remote from thefixed lip translates the forward biasing force of the spring intolateral movement of the cover member to its closed position. Themounting means for the lock mechanism incorporating the dust cover shownin FIGURES 8 and 9 may be the same as that shown in FIGURE 7, and thespring 43 can therefore serve to bias the cap into sealing engagementwith the annular retainer 23 and the retainer into engagement with thepanel 168 on which the lock mechanism is mounted.

From the foregoing description taken together with the accompanyingdrawings it will be apparent that this invention provides an automaticdust cover for the key slot of a cylinder lock, wherein the cover isopened by nothing more than mere rearward inserting movement of the keyinto the key receiving aperture, and which dust cover, because of theabsence of any hinge or pivot connections, is inexpensive and simple tomanufacture and rugged and dependable in service.

What is claimed as my invention is:

1. In a lock of the type wherein a cylinder having a'key receiving slotopening to its front end is rotatable in a bore in a housing, a closurefor the key receiving slot in the cylinder comprising: a cap overlyingthe front of the cylinder and spaced forwardly therefrom, said caphaving portions engaged with the cylinder by which the cap isconstrained to rotate in unison with the cylinder, and having a keyreceiving aperture which is aligned with the mouth of the key receivingslot in the cylinder, said cap also having its rear surface at one sideof said aperture inclined forwardly and laterally toward said aperture;an annular member on the front of the housing providing a sealingconnection between the cap and the housing which permits the cap torotate with the cylinder relative to the housing; a cover member havinga hearing portion which slidingly underlies the rear surface of the capat said side of the aperture in the cap, and a shutter portion whichextends from the bearing portion at a rearwardly inclined angle theretoand is adapted to project beyond the edge of the aperture, the shutterportion of the cover member terminating in a lip; means carried by saidcap providing another lip which opposes the lip on said cover member andis adapted to cooperate therewith to seal the'aperture in the cap; andbiasing means reacting between the front of the cylinder-and said covermember to urge the latter forwardly along said inclined surface on thecap, the lateral component of such forward force on the cover member,due to the inclination of said surface on the cap, holding the lip onthe cover member in sealing engagement with said other lip, said biasingmeans being yieidable to permit the cover member to be camminglypropelled, rearwardly and laterally away from said aperture by a keyinserted through said aperture and moved rearwardly against therearwardly inclined shutter portion of the cover member.

2. The key slot closure of claim 1, wherein the rear surface of the capat the other side of the aperture therein is also inclined forwardly andlaterally toward said aperture; wherein said means providing said otherlip comprises a second cover member, similar to said one cover memberand slidable on the rear surface of the cap at the other side of theaperture in the cap; and wherein other biasing means react between thecylinder and said second cover member to urge the latter forwardly alongthe rear surface of the cap at said other side of the aperture, and inconsequence of the inclination of said surface, laterally toward thefirst cover member.

3. The key slot closure of claim 1, wherein said means providing saidother lip comprises a member fixed on the cap and projecting inwardlyalong that edge of the aperture in the cap which is remote from said onedesignated side thereof.

4. In a lock of the type wherein a cylinder having a key receiving slotopening to its front end is rotatable in a bore in a housing, a closurefor the key receiving slot in the cylinder comprising: a dome-shaped caphaving a medial key receiving aperture and a spherically concave rearsurface providing a forwardly and radially inwardly inclined thrustreceiving surface at each side of the aperture; an annular member on thehousing circumferentially engaged with the cap to hold the cap in frontof and spaced forwardly from the cylinder and providing a seal betweenthe cap and the housing which permits the cap to rotate relative to thehousing; cooperating means on the cylinder and the cap constraining thecap to rotate in unison with the cylinder, with the aperture in the capaligned with the key slot in the cylinder; a pair of cover members, eachhaving a bearing portion with a convex surface that slid'ably seats onone of said thrust receiving surfaces on the cap, and a shutter portionextending from the bearing portion and rearwardly inclined thereto,adapted to project beyond the adjacent edge of the aperture in the capand which terminates in a lip cooperable with the lip on the other covermember to seal the aperture; a rearwardly facing abutment on the bearingportion of each cover member; and a helical compression spring reactingbetween said abutment on each of the cover members and a forwardlyfacing surface on the front of the cylinder to urge the bearing portionof the cover member forwardly along said thrust receiving surface of thecap, the lateral compcnents of such forward forces on the covermember-s, due to the inclination of said surfaces of the cap, urging thecover members laterally toward one another to hold their lips engaged,said springs being yieldable to permit the shutter portions of the covermembers to be carnmingly propelled rearwardly and apart by a keyinserted through said aperture in the cap and moved rearwardly againstthe inclined shutter portions of the cover members.

5. The key slot closure of claim 4 whereineach of said cover members hasan integral elongated strip projecting from the side of its bearingportion remote from its shutter portion, which strip is bent laterallyinwardly to overlie the rear of the bearing portion and provide saidabutment against which the compression spring engages, and thencerearwardly to provide a tang on which the front coils of the compressionspring are piloted.

6. The key slot closure of claim 4 wherein said annular member on thehousing has a circumferential flange on its front which overlies thecircumferential edge portion of the cap, and against which the cap ismaintained sealingly engaged by the forward biasing force of saidsprings acting through the cover members. k

7. The key slot closure of claim 4, further characterized by the factthat the cylinder has wells opening to its front in which the rearmostcoils of the springs are confined and held against lateral displacement.

8. The key slot closure of claim 4, further characterized by the factthat said means for constraining the cap to rotate in unison with thecylinder comprises a plurality of rearwardly projecting fingers on thecap engaged in forwardly opening grooves in the cylinder, so that thecap is free for limited back and forth motion relative to the cylinder.

9. in a lock of the type wherein a cylinder having a key receiving slotopening to its front end is rotatable in a bore in a housing, a closurefor the key receiving slot in the cylinder comprising: means providing acap, connected with the housing and located in forwardly spaced relationto the front of the cylinder and having a key receiving aperture axiallyaligned with the key slot in the cylinder and a thrust receiving surfacewhich generally faces the cylinder but is inclined forwardly toward thekey receiving aperture and extends toward one edge thereof; a covermember having a shutter portion, and a bearing portion which is slidablyand rockably engaged with said thrust receiving surface on the cap tomount the cover member for rocking and sliding motion to and from anormal closed position in which its shutter portion projects beyond saidone edge of the aperture in the cap and toward the other edge thereofand is disposed rearwardly of said edges; and means on the lock exertingforward bias on the bearing portion of the cover member, whereby thecover member is slidingly urged forwardly along said thrust receivingsurface toward said normal closed position thereof, said means beingyieldable to permit the cover member to be cammingly moved to a positionin which its shutter portion is out of alignment with the aperture andthe key slot by means of a key inserted through said aperture and movedrearwardly against the shutter portion of the cover member.

10. The key slot closure of claim 9, further characterized by a fingerprojecting forwardly from the front of the cylinder to within a shortdistance of said thrust receiving surface on the cap and whichcooperates with said thrust receiving surface to substantially confinethe cover member to sliding motion on the thrust receiving surfacetoward and from said position in which the shutter portion of the covermember is out of alignment with the aperture and the key slot.

11. The key slot closure of claim 4, further characterized by the factthat the cylinder has wells opening 10 to its front in which therearmost coils of the springs are confined to be held against lateraldisplacement; and further characterized by a rearwardly projecting tangon each of the cover members engaged in the front coils of the helicalcompression spring reacting against the cover member, said tangsextending rearwardly a sufiicient distance to engage in the mouths ofthe wells when the cover members are moved apart by a key insertedbetween them, to cooperate with the wells in constraining the covermembers to rotate with the cylinder.

References Cited in the file of this patent UNITED STATES PATENTS952,643 Roche Mar. 22, 1910 1,965,942 Jacobi July 10, 1934 2,036,738Zygrnunt Apr. 7, 1936 2,906,112 Vahlstrorn Sept. 29, 1959 FOREIGNPATENTS 638,078 France Feb. 14, 1928

9. IN A LOCK OF THE TYPE WHEREIN A CYLINDER HAVING A KEY RECEIVING SLOTOPENING TO ITS FRONT END IS ROTATABLE IN A BORE IN A HOUSING, A CLOSUREFOR THE KEY RECEIVING SLOT IN THE CYLINDER COMPRISING: MEANS PROVIDING ACAP, CONNECTED WITH THE HOUSING AND LOCATED IN FORWARDLY SPACED RELATIONTO THE FRONT OF THE CYLINDER AND HAVING A KEY RECEIVING APERTURE AXIALLYALIGNED WITH THE KEY SLOT IN THE CYLINDER AND A THRUST RECEIVING SURFACEWHICH GENERALLY FACES THE CYLINDER BUT IS INCLINED FORWARDLY TOWARD THEKEY RECEIVING APERTURE AND EXTENDS TOWARD ONE EDGE THEREOF; A COVERMEMBER HAVING A SHUTTER PORTION, AND A BEARING PORTION WHICH IS SLIDABLYAND ROCKABLY ENGAGED WITH SAID THRUST RECEIVING SURFACE ON THE CAP TOMOUNT THE COVER MEMBER FOR ROCKING AND SLIDING MOTION TO AND FROM ANORMAL CLOSED POSITION IN WHICH ITS SHUTTER PORTION PROJECTS BEYOND SAIDONE EDGE OF THE APERTURE IN THE CAP AND TOWARD THE OTHER EDGE THEREOFAND IS DISPOSED REARWARDLY OF SAID EDGES; AND MEANS ON THE LOCK EXERTINGFORWARD BIAS ON THE BEARING PORTION OF THE COVER MEMBER, WHEREBY THECOVER MEMBER IS SLIDINGLY URGED FORWARDLY ALONG SAID THRUST RECEIVINGSURFACE TOWARD SAID NORMAL CLOSED POSITION THEREOF, SAID MEANS BEINGYIELDABLE TO PERMIT THE COVER MEMBER TO BE CAMMINGLY MOVED TO A POSITIONIN WHICH ITS SHUTTER PORTION IS OUT OF ALIGNMENT WITH THE APERTURE ANDTHE KEY SLOT BY MEANS OF A KEY INSERTED THROUGH SAID APERTURE AND MOVEDREARWARDLY AGAINST THE SHUTTER PORTION OF THE COVER MEMBER.